Coral Reefs

, Volume 27, Issue 3, pp 605–615 | Cite as

Remote video bioassays reveal the potential feeding impact of the rabbitfish Siganus canaliculatus (f: Siganidae) on an inner-shelf reef of the Great Barrier Reef



Herbivores are widely acknowledged as key elements maintaining the health and resilience of terrestrial and aquatic ecosystems. Understanding and quantifying the impact of herbivores in ecosystems are fundamental to our ability to manage these systems. The traditional method of quantifying the impact of herbivorous fishes on coral reefs has been to use transplanted pieces of seagrass or algae as “bioassays”. However, these experiments leave a key question unanswered, namely: Which species are responsible for the impact being quantified? This study revisits the use of bioassays and tested the assumption that the visual abundance of species reflects their role in the removal of assay material. Using remote video cameras to film removal of assay material on an inner-shelf reef of the Great Barrier Reef, the species responsible for assay-based herbivory were identified. The video footage revealed that Siganus canaliculatus, a species not previously recorded at the study site, was primarily responsible for removal of macroalgal biomass. The average percentage decrease in thallus length of whole plants of Sargassum at the reef crest was 54 ± 8.9% (mean ± SE), and 50.4 ± 9.8% for individually presented Sargassum strands (for a 4.5-h deployment). Of the 14,656 bites taken from Sargassum plants and strands across all reef zones, nearly half (6,784 bites or 46%) were taken by S. canaliculatus, with the majority of the remainder attributable to Siganus doliatus. However, multiple regression analysis demonstrated that only the bites of S. canaliculatus were removing macroalgal biomass. The results indicate that, even with detailed observations, the species of herbivore that may be responsible for maintaining benthic community structure can go unnoticed. Some of our fundamental ideas of the relative importance of individual species in ecosystem processes may be in need of re-evaluation.


Herbivory Macroalgae Bioassays Siganus canaliculatus Coral reef Phase-shift 



We wish to thank the staff of Orpheus Island Research Station for facilities and support, C. Mantyka, T. Sunderland and C. Ryen for field support, C. Fulton, A. Hoey and three reviewers for helpful discussions and/or comments on the manuscript, and S. Wismer for help with manuscript preparation. This research was funded by the Australian Research Council and the Great Barrier Reef Marine Park Authority (D. R. Bellwood).

Supplementary material

338_2008_359_MOESM1_ESM.doc (30 kb)
(DOC 30 kb)


  1. Bellwood DR (1994) A phylogenetic study of the parrotfishes, family Scaridae (Pisces: Labroidei), with a revision of genera. Rec Aust Mus Suppl 20:1–86Google Scholar
  2. Bellwood DR, Choat JH (1990) A functional analysis of grazing in parrotfishes (family Scaridae): the ecological implications. Environ Biol Fish 28:189–214CrossRefGoogle Scholar
  3. Bellwood DR, Hoey AS, Choat JH (2003) Limited functional redundancy in high diversity systems: resilience and ecosystem function on coral reefs. Ecol Lett 6:281–285CrossRefGoogle Scholar
  4. Bellwood DR, Hughes TP, Hoey AS (2006) Sleeping functional group drives coral reef recovery. Curr Biol 16:2434–2439PubMedCrossRefGoogle Scholar
  5. Bellwood DR, Hughes TP, Folke C, Nystrom M (2004) Confronting the coral reef crisis. Nature 429:827–833PubMedCrossRefGoogle Scholar
  6. Bryan PG (1975) Food habits, functional digestive morphology and assimilation efficiency of the rabbitfish Siganus spinus (Pisces: Siganidae) on Guam. Pac Sci 29:269–277Google Scholar
  7. Burkepile DE, Hay ME (2006) Herbivore vs. nutrient control of marine primary producers: context-dependent effects. Ecology 87:3128–3139PubMedCrossRefGoogle Scholar
  8. Choat JH (1991) The biology of herbivorous fishes on coral reefs. In: Sale PF (ed) The ecology of fishes on coral reefs. Academic Press, San Diego, pp 120–155Google Scholar
  9. Choat JH, Clements KD, Robbins WD (2002) The trophic status of herbivorous fishes on coral reefs I: Dietary analyses. Mar Biol 140:613–623CrossRefGoogle Scholar
  10. Choat JH, Robbins WD, Clements KD (2004) The trophic status of herbivorous fishes on coral reefs II: Food processing modes and trophodynamics. Mar Biol 145:445–454CrossRefGoogle Scholar
  11. Feeley KJ, Terborgh JW (2005) The effects of herbivore density on soil nutrients and tree growth in tropical forest fragments. Ecology 86:116–124CrossRefGoogle Scholar
  12. Fox RJ, Bellwood DR (2007) Quantifying herbivory across a coral reef depth gradient. Mar Ecol Prog Ser 339:49–59CrossRefGoogle Scholar
  13. Fox RJ, Bellwood DR (in press) Direct versus indirect methods of quantifying herbivore grazing impact on a coral reef. Mar BiolGoogle Scholar
  14. Frank DA, Kuns MM, Guido DR (2002) Consumer control of grassland plant production. Ecology 83:602–606CrossRefGoogle Scholar
  15. Friedlander A M, DeMartini EE (2002) Contrasts in density, size, and biomass of reef fishes between the northwestern and the main Hawaiian islands: The effects of fishing down apex predators. Mar Ecol Prog Ser 230:253–264CrossRefGoogle Scholar
  16. Grandcourt E, Al Abdessalaam T, Francis F, Al Shamsi A (2007) Population biology and assessment of the white-spotted spinefoot, Siganus canaliculatus (Park, 1797), in the southern Arabian Gulf. J Appl Ichthyol 23:53–59CrossRefGoogle Scholar
  17. Hasse JJ, Madraisau BB, McVey JP (1977) Some aspects of the life history of Siganus canaliculatus (Park) (Pisces: Siganidae) in Palau. Micronesica 13:297–213Google Scholar
  18. Hawkins JP, Roberts CM (2004) Effects of artisanal fishing on Caribbean coral reefs. Conserv Biol 18:215–226CrossRefGoogle Scholar
  19. Hay ME (1981) Spatial patterns of grazing intensity on a Caribbean barrier reef: herbivory and algal distribution. Aquat Bot 11:97–110CrossRefGoogle Scholar
  20. Hay ME, Colburn T, Downing D (1983) Spatial and temporal patterns in herbivory on a Caribbean fringing reef the effects on plant distribution. Oecologia 58:299–308CrossRefGoogle Scholar
  21. Hoey AS, Bellwood DR (2007) Cross-shelf variation in the role of parrotfishes on the Great Barrier Reef. Coral Reefs DOI 10.10007/s00338–007-0287xGoogle Scholar
  22. Hughes TP (1994) Catastrophes, phase shifts, and large scale degradation of a Caribbean coral reef. Science 265:1547–1551PubMedCrossRefGoogle Scholar
  23. Hughes TP, Bellwood DR, Folke C, Steneck RS, Wilson J (2005) New paradigms for supporting the resilience of marine ecosystems. Trends Ecol Evol 20:380–386PubMedCrossRefGoogle Scholar
  24. Hughes TP, Rodrigues MJ, Bellwood DR, Ceccarelli D, Hoegh-Guldberg O, McCook L, Moltschaniwskyj N, Pratchett MS, Steneck RS, Willis B (2007) Phase shifts, herbivory and the resilience of coral reefs to climate change. Curr Biol 17:360–365PubMedCrossRefGoogle Scholar
  25. Kuiter RH, Debelius H (2001) Surgeonfishes, rabbitfishes and their relatives. TMC publishing, ChorleywoodGoogle Scholar
  26. Kulbicki M, Guillemot N, Amand M (2005) A general approach to length-weight relationships for New Caledonian lagoon fishes. Cybium 29:235–252Google Scholar
  27. Lapointe BE, Barile PJ, Yentsch CS, Littler MM, Littler DS, Kakuk B (2004) The relative importance of nutrient enrichment and herbivory on macroalgal communities near Norman’s Pond Cay, Exumas Cays, Bahamas: a “natural” enrichment experiment. J Exp Mar Biol Ecol 298:275–301CrossRefGoogle Scholar
  28. Laroche J, Ramananarivo N (1995) A preliminary survey of the artisanal fishery on coral reefs of the Tulear Region (southwest Madagascar). Coral Reefs 14:193–200Google Scholar
  29. Ledlie MH, Graham NAJ, Bythell JC, Wilson SK, Jennings S, Polunin NVC, Hardcastle J (2007) Phase shifts and the role of herbivory in the resilience of coral reefs. Coral Reefs 26:641–653CrossRefGoogle Scholar
  30. Lewis SM (1985) Herbivory on coral reefs algal susceptibility to herbivorous fishes. Oecologia 65:370–375CrossRefGoogle Scholar
  31. Lewis SM (1986) The role of herbivorous fishes in the organization of a Caribbean reef community. Ecol Monogr 56:183–200CrossRefGoogle Scholar
  32. Lewis SM, Wainwright PC (1985) Herbivore abundance and grazing intensity on a Caribbean coral reef. J Exp Mar Biol Ecol 87:215–228CrossRefGoogle Scholar
  33. Littler MM, Littler DS (2007) Assessment of coral reefs using herbivory/nutrient assays and indicator groups of benthic primary producers: a critical synthesis, proposed protocols, and critique of management strategies. Aquat Conservat Mar Freshwat Ecosyst 17:195–215CrossRefGoogle Scholar
  34. Lundberg B, Lipkin Y (1979) Natural food of the herbivorous rabbitfish (Siganus spp.) in Northern Red Sea. Bot Mar 22:173–181CrossRefGoogle Scholar
  35. Mantyka CS, Bellwood DR (2007a) Direct evaluation of macroalgal removal by herbivorous coral reef fishes. Coral Reefs 26:435–442CrossRefGoogle Scholar
  36. Mantyka CS, Bellwood DR (2007b) Macroalgal grazing selectivity among herbivorous coral reef fishes. Mar Ecol Prog Ser 352:177–185CrossRefGoogle Scholar
  37. McClanahan TR, Nugues M, Mwachireya S (1994) Fish and sea urchin herbivory and competition in Kenyan coral reef lagoons: the role of reef management. J Exp Mar Biol Ecol 184:237–254CrossRefGoogle Scholar
  38. McClanahan TR, Hendrick V, Rodrigues MJ, Polunin NVC (1999) Varying responses of herbivorous and invertebrate-feeding fishes to macroalgal reduction on a coral reef. Coral Reefs 18:195–203CrossRefGoogle Scholar
  39. McClanahan T, Sala E, Stickels PA, Cokos BA, Baker AC, Starger CJ, Jones IV SH (2003) Interactions between nutrients and herbivory in controlling algal communities and coral condition on Glover’s Reef, Belize. Mar Ecol Prog Ser 261:135–147CrossRefGoogle Scholar
  40. McCook LJ (1996) Effects of herbivores and water quality on Sargassum distribution on the central Great Barrier Reef: cross-shelf transplants. Mar Ecol Prog Ser 139:179–192CrossRefGoogle Scholar
  41. McNaughton SJ, Banyikwa FF, McNaughton MM (1997) Promotion of the cycling of diet-enhancing nutrients by African grazers. Science 278:1798–1800PubMedCrossRefGoogle Scholar
  42. Mumby PJ, Dahlgren CP, Harborne AR, Kappel CV, Micheli F, Brumbaugh DR, Holmes KE, Mendes JM, Broad K, Sanchirico JN, Buch K, Box S, Stoffle RW, Gill AB (2006) Fishing, trophic cascades, and the process of grazing on coral reefs. Science 311:98–101PubMedCrossRefGoogle Scholar
  43. Nelson SG, Tsutsui RN (1981) Browsing by herbivorous reef fishes on the agarophyte Gracilaria edulis (Rhodophyta) at Guam, Mariana Islands. Proc 4th Int Coral Reef Symp 2:503–508Google Scholar
  44. Paul VJ, Nelson SG, Sanger HR (1990) Feeding preferences of adult and juvenile rabbitfish Siganus argentus in relation to chemical defenses of tropical seaweeds. Mar Ecol Prog Ser 33:255–264CrossRefGoogle Scholar
  45. Pillans RD, Franklin CE, Tibbetts IR (2004) Food choice in Siganus fuscescens: influence of macrophyte nutrient content and availability. J Fish Biol 64:297–309CrossRefGoogle Scholar
  46. Randall JE (1965) Grazing effect on sea grasses by herbivorous reef fishes in the West Indies. Ecology 46:255–260CrossRefGoogle Scholar
  47. Randall JE, Allen GR, Steene RC (1997) Fishes of the Great Barrier Reef and Coral Sea. Crawford House Publishing Pty. Ltd., BathurstGoogle Scholar
  48. Reinthal PN, Macintyre IG (1994) Spatial and temporal variations in grazing pressure by herbivorous fishes: Tobacco Reef, Belize. Atoll Res Bull 425:1–11Google Scholar
  49. Sabapathy U, Teo LH (1995) Some properties of the intestinal proteases of the rabbitfish Siganus canaliculatus (Park). Fish Physiol Biochem 14:215–21CrossRefGoogle Scholar
  50. Saito H, Yamashiro R, Alasalvar C, Konno T (1999) Influence of diet on fatty acids of three subtropical fish, subfamily caesioninae (Caesio diagramma and C. tile) and family siganidae (Siganus canaliculatus). Lipids 34:1073–1082PubMedCrossRefGoogle Scholar
  51. Sluka RD, Miller MW (2001) Herbivorous fish assemblages and herbivory pressure on Laamu Atoll, Republic of Maldives. Coral Reefs 20:255–262CrossRefGoogle Scholar
  52. Steneck RS (1983) Quantifying herbivory on coral reefs: just scratching the surface and still biting off more than we can chew. In: Reaka ML (ed) The ecology of deep and shallow coral reefs, Vol 1 NOAA’s Undersea Research Program, US Department of Commerce, Washington, DC, pp 103–111Google Scholar
  53. Steneck RS, Hacker SD, Dethier MN (1991) Mechanism determining competitive dominance between crustose coralline algae: a herbivore-mediated reversal. Ecology 72:938–950CrossRefGoogle Scholar
  54. Streelman JT, Alfaro M, Westneat MW, Bellwood DR, Karl SA (2002) Evolutionary history of the parrotfishes: biogeography, ecomorphology, and comparative diversity. Evolution 56:961–971PubMedGoogle Scholar
  55. Tsuda RT, Bryan PG (1973) Food preference of juvenile Siganus rostratus and S. spinus in Guam. Copeia 1973:604–606CrossRefGoogle Scholar
  56. von Westernhagen H (1973) The natural food of the rabbitfish Siganus oramin and S. striolata. Mar Biol 22:367–370CrossRefGoogle Scholar
  57. Wantiez L, Thollot P, Kulbicki M (1997) Effects of marine reserves on coral reef fish communities from five islands in New Caledonia. Coral Reefs 16:215–224CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  1. 1.Australian Research Council Centre of Excellence for Coral Reef Studies and School of Marine and Tropical BiologyJames Cook UniversityTownsvilleAustralia

Personalised recommendations